Magnetically operable multiple reed contact

ABSTRACT

In this multiple, magnetically-operable bistable reed arrangement, the reed tube contains two electrically separated, polarized contact sets each of which consists of two contact arms and an armature permanently connected to and magnetically separated from one of the contact arms. The respective associated contact arms are brought out as contact terminals at the same end of the reed tube and form, inside the reed tube, a magnetic operating air gap along with the free end of the armature, which projects into the space between the contact arms. Each of the armatures is suspended from one of the two associated contact arms by a non-magnetic spring, with the armatures being so arranged as to overlap each other considerably in order to mutually assist each other in their magnetic coupling when the operating coil is excited.

1111 3,771,083 Nov. 6, 1973 MAGNETICALLY OPERABLE MULTIPLE REED CONTACT Gerhard Wessel, Kornwestheim, Germany Inventor:

Assignee: International Standard Electric Corporation, New York, N.Y.

Filed: Aug. 29, 1972 Appl. No.: 284,526

Foreign Application Priority Data Sept. 6, 1971 Germany P 21 44 538.5

US. Cl. 335/153 Int. Cl. H0lh 51/22, l-lOlh 51/28 Field of Search 335/151, 153, 154

2/1967 Shaw et al. 335/154 10/1967 Grengg 335/154 Primary ExaminerRoy N. Envall, Jr. Attorney-C. Cornell Remsen, Jr. et al.

[5 7 ABSTRACT In this multiple, magnetically-operable bistable reed arrangement, the reed tube contains two electrically separated, polarized contact sets each of which consists of two contact arms and an armature permanently connected to and magnetically separated from one of the contact arms. The respective associated contact arms are brought out as contact terminals at the sameend of the reed tube and form, inside the reed tube, a magnetic operating air gap along with the free end of the armature, which projects into the space betweenv the contact arms. Each of the armatures is suspended from one of the two associated contact arms bya nonmagnetic spring, with the armatures being so arranged as to overlap each other considerably in order to mutually assist each other in their magnetic coupling when the operating coil is excited.

9 Claims, 5 Drawing Figures PATENIEDHBV suns 3771.083

I '@SHEETlGF2 MAGNETICALLY OPERABLE MULTIPLE REED CONTACT BACKGROUND OF THE INVENTION The present invention relates to a magnetically operable multiple reed contact in which several contacts with contact elements of different lengths are arranged in a common reed tube and in which the operating air gaps of the contact sets contained in the reed tube are located in different planes intersecting the longitudinal axis of the reed tube.

Reed contacts of this type are known; however, embodiments thereof are generally not suitable for" polarized, bistable switching.

A particular prior art arrangement employs a med contact containing a polarized contact setwhosecontact arms are brought out as contact terminals at the same end of the reed tube and whose armature is" mounted on one of the contact arms and connected therewith not only electrically, but also magnetically. This sets up a magnetic parallel'to the armaturewhich shorts partof the flux necessary for switching, so that this unbalance places one contact arm eta-magnetic disadvantage. In addition, the arrangement shown and described there requires two such reed contacts" for pulse-controlledbistable switching.

SUMMARY OF THE INVENTION It is the object of the present invention to'provide' a pulse-controlled double contact whose armatures'are mechanically and electrically connected in sucl'r'a rn'anner that the magnetic disadvantage of one contact h'alf does not exist. The invention is characterized zin' that the reed tube contains two electrically separated, polarized contact setseach of which consists oftwocontact arms and one armature permanently connected to and magnetically separated from anendof one'ofsaid contact arms, with each pair of contact arms broughtout as-contact terminals at the same end of thenreedtube and forming, inside the reedtube; a magnetic op erating air gapv along the free end of the armature,

whichXend projects into thespace between the'contact:

arms. This arrangementis largely balanced, and the-opierating air gap, in which the free endzof the armature moves, acts, unlike in the particular priorart arrangement eluded to above, as a real differential air-gap.

In one embodiment of the invention, each of the.ar-' matures is suspended from one of two associated contact arms by means of an entirely or partially nonmagnetic spring. This type of armature mounting largely mitigates the magnetic short-circuit occurring in the known arrangement.

In a further embodiment of the invention, aperma nent magnet is disposed at each of the ends ofthe reed tube between the associated contact terminals.- In' a further embodiment of the invention, use may alsobe made of a common. permanent magnet for polarizing several contact sets arranged side by side in different reed tubes. I

In still another embodiment of the invention, thearmature isa permanent magnet.

At the occurrence of a coid-produced electromag-. netic field which provides the flux necessary for switch ing, the two contact sets within a reed tube, in a further embodiment of the invention, mutually assist eachother in their magnetic coupling. To this end, the armatures of the two contact sets are arranged in the reed' tube side by side and with a large overlap and are spaced a short distance apart.

Another embodiment of the invention is characterized in'that the respective free contact arm has a nonmagnetic, resilient contact maker mounted thereto whose contact area, directed toward the armature, lies closer to'the contact-making end of the armature than the contact area of the magnetically conducting free contact arm, facing the armature. By this separation between the electrical and the magnetic contact'point, a small gap is obtained between the armature and the contact arm when the armature makes contact with the contact maker. A further reduction of the gap causes a frictional movement on the contact surface as well as increasing contact force until the armature rests against the contact arm. This embodiment is almost bouncefree.

Instill another embodiment of the invention, the associated'cont'act terminals are interconnected by a U- shaped piece which is detachable outside the reed tube after sealing. Such a reed contact can be made very economically because the two contact sets can be preformed'as'a unit before being introduced into the reed tube. This eliminates the need for the adjustment of the operating air gaps during sealing.

The above described reed contact may be used in telephone switching networks and in polarized relays switched with short pulses only. During. switching, the magnetic differential air gap prevents the contact from re-opening and the armature from pulling up again. The volume" for the contact set'of this reed contact is only half as large as that for a known reed contact because'practically two electrically separated contact sets 35 are housed in the same space.

BRIEF'DESCRIPTION OF THE DRAWINGS The invention will now be explained 'withreference to embodiments thereof which areillustrated' in the accompanyingdrawings, and in which:

FIG. 1 is a sectional side view of 'a reed contact surrounded by an operating coil;

FIG. 2 shows the contact elements of the contact set contained in the reed contact of FIG.- 1, with a special design of the contact point;

FIG. 3 is a sectional side view of another embodiment of a reed contact;

FIG. 4 is a fragmentary top plan view of a common permanent magnet associated with several contact sets indifferent reed tubes; and

FIG; 5 is a fragmentary sectional side view of one contact set of FIGS. 1 or 3 where the armature is a permanent magnet.

DESCRIPTION OF THE PREFERRED EMBODIMENTS contact set 2, 3 consists of two contact arms 6, 7 and 8, 9, respectively, and an armature l0 and 11, respectively, magnetically separated from the endsof contact arms 6, 7 and 8, 9, respectively. Each pair of contact arms 7 and 9 is brought out as contact terminals l2, l3 and 14, 15, respectively, at the same end of the reed tube 1.

The armatures 10 and 11 are permanently connected to and magnetically separated from one end of one of two associated contact arms 7 and 9, respectively, by non-magnetic intermediate pieces 16 and 17 and the free ends of armatures 10 and l 1 project into the space between and move between the contact arms 6, 7 and 8,9, respectively, dependent upon the operation of coil 20. The non-magnetic intermediate pieces 16 and 17 are necessary in order that the magnetic flux is interrupted along contact arms 7 and 9 so as to prevent a magnetic flux short circuit path with regard to the magnetic flux path between the contact arms and the free, moving ends of their associated armatures. Since the armatures l and 11 are connected with the ends of the contact arms 7 and 9, respectively, via non-magnetic intermediate pieces 16 and 17, respectively, real differential air gaps are obtained in which the free ends of the armatures and 11, respectively, move. The phrase a real differential air gap refers to the operation of the armature, e.g. armature 11 in air gap 5 which is as follows. The permanent magnetic flux extends from the permanent magnet 19 through contact terminal 14, contact arm 8, air gap 5, contact arm 9, contact terminal and back to permanent magnet 19. In contrast, the electromagnetic flux of the operating coil 20 when excited is fed from the free end of annatui'e 11 into air gap 5 in such a manner that the electromagnetic flux, which divides between the contact arms 8 and 9, is equal in direction to the permanent magnetic flux between armature 11 and contact arm 8, for example, and opposite in direction to the permanent magnetic flux between armature l1 and contact arm 9.

This produces a real differential effect such as found in a conventional telegraph relay.

Located between the associated contact terminals l2, l3 and l4, 15 at the two ends of the reed tube 1 are permanent magnets 18 and 19, respectively. These permanent magnets may also be designed so that they serve to polarize several contact sets arranged side by side in different reed tubes as illustrated in FIG. 4. The reed tube 1 is enclosed by an operating coil 20.

Following is a description of the operation of the illustrated polarized bistable switching relay. The magnetic circuit is designed so that the switching operation depends on the direction of the exciting current and on the resulting magnetic flux. This relay is bistable because the armatures 10 and l l are held in each of their operating positions by the polarizing flux of the perma-' nent magnets 18 and 19, respectively, if no current flows in the operating coil 20. The magnetic circuit is largely balanced, so that the armatures 10, 11 change to the opposite position when the operating coil 20 is excited with the proper polarity. The flux produced by the operating coil 20 increases or reduces the attractive force of the permanent magnets 18 and 19 approximately in proportion to the square of the sum or difference of the flux values. The armatures l0 and 1 1 adhere to the contact arms 6 or 7 and 8 or 9, respectively, with the greater total flux. The use of a permanent magnetic holding flux permits better utilization of the coil It may appear that when coil 20 is energized that armatures 10 and 11 would come in contact and thereby short the two contact sets. While there is a certain attraction between armatures l0 and 11 actual contact does not occur due to the large area overlap and to the large air gap between armatures 10 and 11 as compared to the small overlap at the small operating air gaps 4 and 5. As a result the flux attraction between armatures 10 and 11 is considerably smaller than that in the operating air gaps 4 and 5.

As a modification to the embodiment shown in FIG. 1, the armatures 10 and 11 may themselves be pennanent magnets as illustrated in FIG. 5. In this modification of FIG. 1 permanent magnets 18 and 19 are no longer needed and therefore may be eliminated. In another modification, this contact may also be used as a normal make contact.

The contact sets 2 and 3 are arranged in the reed tube 1 so as to mutually assist each other in their magnetic coupling if the operating coil 20, providing the. flux necessary for switching, is excited. Therefore, the armatures l0 and 11 of the two contact sets 2 and 3 are arranged in the reed tube side by side and with a large a U-shaped piece 21. Thus, the contact sets, e.g.'3, can

be preformed before being introduced into the reed tube 1 and the adjustment of the operating air gaps, e.g. 5, can be carried out prior to that introduction.

Following the sealing operation, the U-shaped piece 21 is detached outside the reed tube 1.

FIG. 2 shows an almost bounce-free contact design whose free contact arm 6a has a non-magnetic, resilient contact maker 22 mounted thereto, whose contact area, directed toward the armature 10a, lies closer to the contact-making end of the armature 10a than that of the contact arm 6a, facing the armature 10a. This difference in spacing is designated d in FIG. 2. In this embodiment, the impingement of the armature 10a on the electrical contact point causes a frictional movement by which contamination layers on the contact areas can be removed. In addition, the contact force becomes independent of the magnetic holding force.

FIG. 3 shows another reed contact in which the armatures 10b and 11b are suspended from one of two associated contact arms 7b and 9b, respectively, by means of entirely or partially non-magnetic springs 23 and 24, respectively. The remaining structure and the mode of operation of this reed contact correspond to the double contact described in connection with FIG.

While I have described above the principles of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way 'of example and not as a limitation to the scope of sists of two contact arms and one armature permanently connected to and magnetically separated from an end of one of said contact arms, with each pair of contact arms brought out as contact terminals at the same end of the reed tube and forming, inside the reed tube, a magnetic operating air gap along with the free end of the armature, which projects into the space between the contact arms.

2. The reed contact according to claim 1 wherein each of the armatures is suspended from one of two associated contact arms by means of non-magnetic springs.

3. The reed contact according to claim 2 wherein a permanent magnet is located at each of the two ends of the reed tube between the associated contact terminals.

4. The reed contact according to claim 3 further including a common permanent magnet for polarizing several contact sets arranged side by side in different reed tubes.

5. The reed contact according to claim 2 wherein the armature is a permanent magnet.

6. The reed contact according to claim 1 wherein the two contact sets are arranged within a reed tube to mutually assist each other in their magnetic coupling.

7. The reed contact according to claim 6 wherein the armatures of the two contact sets are arranged in the reed tube side by side and with a large overlap and are closely spaced apart.

8. The reed contact according to claim 2 wherein at the free contact arm there is provided a non-magnetic, resilient contact maker whose contact area, directed toward the armature lies closer to the contact-making end of the armature than the contact area of the magnetically conducting free contact arm, facing the annature.

9. The reed contact according to claim 1 wherein the associated contact terminals are interconnected by a U-shaped piece, which is detachable outside the reed tube after the sealing operation. 

1. A magnetically operable multiple reed contact in which several contacts with contact elements of different lengths are arranged in a common reed tube and in which the operating air gaps of the contact sets contained in the reed tube are located in different planes intersecting the longitudinal axis of the reed tube, characterized in that the reed tube contains two electrically separated, polarized contact sets, each of which consists of two contact arms and one armature permanently connected to and magnetically separated from an end of one of said contact arms, with each pair of contact arms brought out as contact terminals at the same end of the reed tube and forming, inside the reed tube, a magnetic operating air gap along with the free end of the armature, which projects into the space between the contact arms.
 2. The reed contact according to claim 1 wherein each of the armatures is suspended from one of two associated contact arms by means of non-magnetic springs.
 3. The reed contact according to claim 2 wherein a permanent magnet is located at each of the two ends of the reed tube between the associated contact terminals.
 4. The reed contact according to claim 3 further including a common permanent magnet for polarizing several contact sets arranged side by side in different reed tubes.
 5. The reed contact according to claim 2 wherein the armature is a permanent magnet.
 6. The reed contact according to claim 1 wherein the two contact sets are arranged within a reed tube to mutually assist each other in their magnetic coupling.
 7. The reed contact according to claim 6 wherein the armatures of the two contact sets are arranged in the reed tube side by side and with a large oVerlap and are closely spaced apart.
 8. The reed contact according to claim 2 wherein at the free contact arm there is provided a non-magnetic, resilient contact maker whose contact area, directed toward the armature lies closer to the contact-making end of the armature than the contact area of the magnetically conducting free contact arm, facing the armature.
 9. The reed contact according to claim 1 wherein the associated contact terminals are interconnected by a U-shaped piece, which is detachable outside the reed tube after the sealing operation. 